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    <title>Document</title>
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<body>
    <!-- 检测昵称是否是有汉字字母数字下划线组成，6-8位 -->
    <script>
        let str1 = "12565_ab"
        let str2 = "1 5 65 _ a b"
        let str3 = "1565_#ab"
        let str4 = "15_ab"
        let reg = /^\w{6,8}$/
        console.log(reg.test(str1))
        console.log(reg.test(str2))
        console.log(reg.test(str3))
        console.log(reg.test(str4))
    </script>
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